GENERALIZED MAGNETORHEOLOGICAL (MR) DAMPER MODEL AND ITS APPLICATION IN SEMI-ACTIVE CONTROL OF VEHICLE SUSPENSION SYSTEM

L. BALAMURUGAN,J. JANCIRANI,M. A. ELTANTAWIE 한국자동차공학회 2014 International journal of automotive technology Vol.15 No.3

In this paper, analytical characterization of the magneto-rheological (MR) damper is done using a new modifiedalgebraic model. Algebraic model is also more preferable because of its low computational expenses compared to differentialBouc-Wen’s model which is highly computationally demanding. This model along with the obtained model parameters is usedas a semi-active suspension device in a quarter car model and the stationary response of the vehicle traversing on a rough roadis obtained. The control part consists of two nested controllers. One of them is the system controller which generates thedesired damping force and the other is the damper controller which adjusts the voltage level to MR damper so as to track thedesired damping force. For the system controller a model reference skyhook Sliding Mode Controller (SMC) is used and forthe damper controller a continuous state algorithm is built to determine the input voltage so as to gain the desired dampingforce. The analytical model is subsequently used in the quarter car vehicle model and the vehicular responses are studied. Asimulation study is performed to prove the effectiveness and robustness of the semi-active control approach. Results show thatthe semi-active controller can achieve compatible performance as that of active suspension controller except for a littledeterioration.

Design and optimization of concurrent tolerance in mechanical assemblies using bat algorithm

L. Ramesh Kumar,K. P. Padmanaban,S. Ganesh Kumar,C. Balamurugan 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.6

Concurrent designing of tolerance has become a vital concern in product and process development due to the relationship between quality, functionality and product cost. It is one of the well explored areas in combinatorial optimization. In this paper, a recently developed optimization algorithm, called Bat algorithm (BA), is used for optimizing the tolerance based on concurrent objectives to minimize the manufacturing cost, present worth of expected quality loss and quality loss. The mechanical assemblies such as Bevel gear assembly (A), Gear box assembly (B) and Suction union assembly (C) are considered to demonstrate the proposed algorithm. It is found that the BA has produced better results than other methods in initial generations for concurrent tolerance problems.

Analysis of Tunnelling Rate Effect on Single Electron Transistor

Sheela. L,N. B. Balamurugan,S. Sudha,J. Jasmine 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.5

This paper presents the modeling of Single Electron Transistor (SET) based on Physical model of a device and its equivalent circuit. The physical model is derived from Schrodinger equation. The wave function of the electrode is calculated using Hartree-Fock method and the quantum dot calculation is obtained from WKB approximation. The resulting wave functions are used to compute tunneling rates. From the tunneling rate the current is calculated. The equivalent circuit model discuss about the effect of capacitance on tunneling probability and free energy change. The parameters of equivalent circuit are extracted and optimized using genetic algorithm. The effect of tunneling probability, temperature variation effect on tunneling rate, coulomb blockade effect and current voltage characteristics are discussed.

Surface Modification of Droplet Polymeric Microfluidic Devices for the Stable and Continuous Generation of Aqueous Droplets

Subramanian, Balamurugan,Kim, Namwon,Lee, Wonbae,Spivak, David A.,Nikitopoulos, Dimitris E.,McCarley, Robin L.,Soper, Steven A. American Chemical Society 2011 Langmuir Vol.27 No.12

<P>Droplet microfluidics performed in poly(methyl methacrylate) (PMMA) microfluidic devices resulted in significant wall wetting by water droplets formed in a liquid–liquid segmented flow when using a hydrophobic carrier fluid such as perfluorotripropylamine (FC-3283). This wall wetting led to water droplets with nonuniform sizes that were often trapped on the wall surfaces, leading to unstable and poorly controlled liquid–liquid segmented flow. To circumvent this problem, we developed a two-step procedure to hydrophobically modify the surfaces of PMMA and other thermoplastic materials commonly used to make microfluidic devices. The surface-modification route involved the introduction of hydroxyl groups by oxygen plasma treatment of the polymer surface followed by a solution-phase reaction with heptadecafluoro-1,1,2,2-tetrahydrodecyl trichlorosilane dissolved in fluorocarbon solvent FC-3283. This procedure was found to be useful for the modification of PMMA and other thermoplastic surfaces, including polycyclic olefin copolymer (COC) and polycarbonate (PC). Angle-resolved X-ray photoelectron spectroscopy indicated that the fluorination of these polymers took place with high surface selectivity. This procedure was used to modify the surface of a PMMA droplet microfluidic device (DMFD) and was shown to be useful in reducing the wetting problem during the generation of aqueous droplets in a perfluorotripropylamine (FC-3283) carrier fluid and could generate stable segmented flows for hours of operation. In the case of PMMA DMFD, oxygen plasma treatment was carried out after the PMMA cover plate was thermally fusion bonded to the PMMA microfluidic chip. Because the appended chemistry to the channel wall created a hydrophobic surface, it will accommodate the use of other carrier fluids that are hydrophobic as well, such as hexadecane or mineral oils.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/langd5/2011/langd5.2011.27.issue-12/la200298n/production/images/medium/la-2011-00298n_0005.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/la200298n'>ACS Electronic Supporting Info</A></P>

Reliability of Galvanostatic Pulse Technique in assessing the corrosion rate of rebar in concrete structures: Laboratory vs field studies

Vedalakshmi, R.,Balamurugan, L.,Saraswathy, V.,Kim, S. H.,Ann, K. Y. Springer Science + Business Media 2010 KSCE JOURNAL OF CIVIL ENGINEERING Vol.14 No.6

Evaluation of Composite Cements using Cyclic Polarization Techniques

V. Saraswathy,S. Muralidharan,L. Balamurugan,P. Kathirvel,A. S. S. Sekar 대한토목학회 2011 KSCE JOURNAL OF CIVIL ENGINEERING Vol.15 No.8

Slag Cement (PSC) extracts in the presence and absence of nitrite inhibitor were studied by cyclic polarization technique. Studies also carried out in composite (binary and ternary) cement extracts. The re-passivation potential (Erep) is an important parameter to characterize the corrosion resistant property of cements and the efficiency of inhibitor. Blended cements (PPC and PSC) have higher tolerable limit of chloride than OPC. Binary cements increase the tolerable limit of chloride than individual cements. The passivity of steel maintained by ternary cement was found to be less than 45000 ppm of chloride along with 5000 ppm of nitrite (pitting occurred at 45000 ppm). This chloride level is more than that of chlorides in natural sea water (35000 ppm). Hence the use of composite cement especially in marine atmosphere increases the corrosion resistance of steel in concrete.

Simple replication methods for producing nanoslits in thermoplastics and the transport dynamics of double-stranded DNA through these slits

Chantiwas, Rattikan,Hupert, Mateusz L.,Pullagurla, Swathi R.,Balamurugan, Subramanian,Tamarit-Ló,pez, Jesú,s,Park, Sunggook,Datta, Proyag,Goettert, Jost,Cho, Yoon-Kyoung,Soper, Steven A. Royal Society of Chemistry 2010 Lab on a chip Vol.10 No.23

<P>Mixed-scale nano- and microfluidic networks were fabricated in thermoplastics using simple and robust methods that did not require the use of sophisticated equipment to produce the nanostructures. High-precision micromilling (HPMM) and photolithography were used to generate mixed-scale molding tools that were subsequently used for producing fluidic networks into thermoplastics such as poly(methyl methacrylate), PMMA, cyclic olefin copolymer, COC, and polycarbonate, PC. Nanoslit arrays were imprinted into the polymer using a nanoimprinting tool, which was composed of an optical mask with patterns that were 2–7 µm in width and a depth defined by the Cr layer (100 nm), which was deposited onto glass. The device also contained a microchannel network that was hot embossed into the polymer substrate using a metal molding tool prepared <I>via</I> HPMM. The mixed-scale device could also be used as a master to produce a polymer stamp, which was made from polydimethylsiloxane, PDMS, and used to generate the mixed-scale fluidic network in a single step. Thermal fusion bonding of the cover plate to the substrate at a temperature below their respective <I>T</I><SUB>g</SUB> was accomplished by oxygen plasma treatment of both the substrate and cover plate, which significantly reduced thermally induced structural deformation during assembly: ∼6% for PMMA and ∼9% for COC nanoslits. The electrokinetic transport properties of double-stranded DNA (dsDNA) through the polymeric nanoslits (PMMA and COC) were carried out. In these polymer devices, the dsDNA demonstrated a field-dependent electrophoretic mobility with intermittent transport dynamics. DNA mobilities were found to be 8.2 ± 0.7 × 10<SUP>−4</SUP> cm<SUP>2</SUP> V<SUP>−1</SUP> s<SUP>−1</SUP> and 7.6 ± 0.6 × 10<SUP>−4</SUP> cm<SUP>2</SUP> V<SUP>−1</SUP> s<SUP>−1</SUP> for PMMA and COC, respectively, at a field strength of 25 V cm<SUP>−1</SUP>. The extension factors for λ-DNA were 0.46 in PMMA and 0.53 in COC for the nanoslits (2–6% standard deviation).</P> <P>Graphic Abstract</P><P>Thermoplastic nanoslits were replicated from a simple molding tool and consisted of mixed-scale structures with successful DNA translocation through the slits demonstrated. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c0lc00096e'> </P>

Self-Compacting Concrete Using Marble Sludge Powder and Crushed Rock Dust

M. Shahul Hameed,A. S. S. Sekar,L. Balamurugan,V. Saraswathy 대한토목학회 2012 KSCE JOURNAL OF CIVIL ENGINEERING Vol.16 No.6

Self Compacting Concrete (SCC) has had a remarkable impact on the concrete construction industry, especially the precast concrete industry. Crushed Rock Dust (CRD) and Marble Sludge Powder (MSP) are discarded in the nearby land and the natural fertility of the soil is spoiled. MSP and CRD can be used as filler and helps to reduce the total voids content in concrete. Consequently, this contributes to improve the strength of concrete. An experimental investigation has been carried out to study the combined effect of addition of MSP and CRD on the strength and durability of SCC. The study on physical, chemical and mechanical properties such as compressive strength and split tensile strength and the durability tests include water absorption test, water permeability, rapid chloride permeability; electrical resistivity and half cell potential are carried out in this study. From the results it is confirmed that compressive strength increases with increase in percentage replacement of MSP up to 15% of CRD in place of FA. It is found that split tensile strength is directly proportional to the compressive strength. The highest electrical resistivity values were obtained for Normal Concrete with 100% CRD and significant increase in resistivity values for SCC. Self Compacting Concrete (SCC) has had a remarkable impact on the concrete construction industry, especially the precast concrete industry. Crushed Rock Dust (CRD) and Marble Sludge Powder (MSP) are discarded in the nearby land and the natural fertility of the soil is spoiled. MSP and CRD can be used as filler and helps to reduce the total voids content in concrete. Consequently, this contributes to improve the strength of concrete. An experimental investigation has been carried out to study the combined effect of addition of MSP and CRD on the strength and durability of SCC. The study on physical, chemical and mechanical properties such as compressive strength and split tensile strength and the durability tests include water absorption test, water permeability, rapid chloride permeability; electrical resistivity and half cell potential are carried out in this study. From the results it is confirmed that compressive strength increases with increase in percentage replacement of MSP up to 15% of CRD in place of FA. It is found that split tensile strength is directly proportional to the compressive strength. The highest electrical resistivity values were obtained for Normal Concrete with 100% CRD and significant increase in resistivity values for SCC.